The present invention relates generally to a method and an apparatus for increasing the capacity and stability of a single-pole tower. More particularly, the invention relates to a method and an apparatus that employs a sleeve and an array of load transfer pins to add structural stability to a single-pole tower and thereby increase its capacity to support additional equipment and withstand environmental loads.
The increase in wireless telecommunications traffic has resulted a concomitant increase in the need for pole-mounted transmission equipment of all kinds. Not only do wireless service providers need to install equipment covering new geographic areas, competing service providers and others also need to install additional equipment covering the same or similar geographic areas. To date, the solution to both problems normally includes purchasing additional land or easements, applying for the necessary government permits and zoning clearances, and constructing a new tower for the new transmission equipment.
Purchasing land or easements, however, is becoming increasingly expensive, particularly in urban areas where the need for wireless telecommunications is greatest. Zoning regulations often limit the construction of new towers in the vicinity of existing towers or may prohibit the construction of new towers in the most suitable locations. The expense and delay associated with the zoning process often may be cost-prohibitive or so time-consuming that construction of the new tower is not feasible. Even when zoning regulations can be satisfied and permits can be obtained, the service provider must then bear the burden and expense associated with the construction and the maintenance of the tower.
The tower itself must be designed to support the weight of the telecommunications transmission equipment as well as the forces exerted on the pole by environmental factors such as wind and ice. The equipment and the environmental factors produce forces known as bending moments that, in effect, may cause a single-pole tower to overturn if not designed for adequate stability. Traditionally, single-pole towers have been designed to withstand the forces expected from the equipment originally installed on the pole. Very few single-pole towers, however, are designed with sufficient stability to allow for the addition of new equipment.
Thus, there is a need for a method and an apparatus for increasing the capacity and stability of a single-pole tower that will support the weight of additional equipment and support the additional environmental forces exerted on the pole. At best, the prior art shows various brackets used for restoring the strength of a weakened or damaged section of a wooden pole. An example of a known pole restoration system is shown in U.S. Pat. No. 4,991,367 to McGinnis entitled, xe2x80x9cApparatus and Method for Reinforcing a Wooden Pole.xe2x80x9d This reference describes an apparatus that employs a series of braces linked together around the circumference of a tapered pole. The braces are then forced downward on the pole to wedge the assembly tightly against the pole to provide support. This system does not include an anchorage to the ground or base of the pole.
A number of other known pole restoration systems employ a first part attached to the damaged section of the pole and a second part that is driven into the ground to provide support. An example of such a system is shown in U.S. Pat. No. 4,756,130 to Burtelson entitled, xe2x80x9cApparatus for Reinforcing Utility Poles and the Like.xe2x80x9d This apparatus uses a series of brackets and straps attached to ground spikes. Another example of a known pole restoration system is shown in U.S. Pat. No. 4,697,396 to Knight entitled, xe2x80x9cUtility Pole Support.xe2x80x9d This reference describes an apparatus with a series of brackets attached to a wooden utility pole. A series of tapered spikes are anchored on the brackets and then driven into the ground to provide support. Additional examples of such a system are shown in U.S. Pat. Nos. 5,345,732 and 5,815,994, both issued to Knight and Murray, entitled xe2x80x9cMethod and Apparatus for Giving Strength to a Polexe2x80x9d and xe2x80x9cStrengthening of Poles,xe2x80x9d respectively. These references describe an apparatus with a nail or bridging beam driven through the center of the wooden pole. The nail is attached by linkages to a series of circumferential spikes that are then driven into the ground to provide support.
In each of these systems, the brackets are fixably attached to a damaged wooden utility pole to provide a firm anchor for the ground spikes. The spikes are driven into the ground immediately adjacent the pole to wedge the spike tightly against the side of the pole. The functionality of each of these systems depends, therefore, on the rigid attachment between the pole brackets and the spikes as well as the compression fit of the spikes between the ground and the pole. Further, these ground-based systems only function when the damaged pole section is sufficiently near the ground for the bracket assembly to be attached to the ground spikes. The capacity of these known systems to resist bending moments is dependent upon the height of the damaged section relative to the ground as well as the characteristics of the soil and other natural variables. Moreover, each of these systems describes an apparatus for the purpose of restoring a damaged pole to its original capacity, not for the purpose of bolstering an existing pole to increase its capacity.
Thus, there remains a need for a method and apparatus for increasing the capacity and stability of a single-pole tower that will support the weight of additional equipment and support the additional environmental forces exerted on the pole, while providing sufficient stability to resist the forces known as bending moments exerted by the new equipment and the environmental forces. Such a method and an apparatus should accomplish these goals in a reliable, durable, low-maintenance, and cost-effective manner.
The present invention provides a method and an apparatus for increasing the capacity and stability of a single-pole tower. The invention thus provides a support structure for use with an existing single pole tower. The single pole tower has a pole anchored to a foundation and supports a first load. The support structure has a number of sleeves surrounding the pole. The sleeves may extend beyond the height of the existing single pole tower. A first one of the sleeves is anchored to the foundation. A second load is attached to a second one of the sleeves.
Specific embodiments of the present invention include the sleeves being made out of a metal such as a structural pipe with a minimum yield stress of about 42 ksi. The sleeves may have a first half and a second half. Each half may have a first side with a first sleeve tab and a second side with a second sleeve tab. The sleeve tabs may have a number of apertures positioned therein. The sleeves also may include a first end with a first flange plate and a second end with a second flange plate. The flange plates also may have a number of apertures positioned therein. The sleeves also may include a number of load transfer pins. The load transfer pins may have a bolt and one or more nuts. The pins extend from the sleeves to the pole so as to stabilize the loads. The pins may be radially spaced around a vertical center axis of the sleeves. The sleeves may include a plurality of access ports positioned therein. The second load may include one or more telecommunications arrays.
There may be a number of sleeves, such as a first sleeve, a second sleeve, and a third sleeve. The second flange plate of first sleeve is anchored to the foundation. The first flange plate of the first sleeve may include a dimension to accommodate the second flange plate of the second sleeve while the first flange plate of the second sleeve may include a dimension to accommodate the second flange plate of the third sleeve. The first end of the third sleeve may include a cover plate.
Another embodiment of the present invention provides a support structure for supporting a first load and for use with an existing single pole tower. The single pole tower includes a pole anchored to a foundation. The pole supports a second load. The support structure includes a first sleeve attached to the foundation and a second sleeve attached to the first sleeve. The first load is attached to the second sleeve. The sleeves surround the pole. The second sleeve may be attached to the first sleeve via one or more joinder sleeves.
A further embodiment of the present invention provides a support structure for supporting a load and for use with an existing single pole tower. The single pole tower may include a pole anchored to a foundation. The support structure may include a number of sleeves surrounding the pole. One of the sleeves may be anchored to the foundation and another one of the sleeves may support the load. A number of load transfer pins may be positioned along the sleeves. The pins extend from the sleeves to the pole so as to stabilize the load.
A further embodiment of the present invention provides a support structure for supporting a load. The support structure includes a single pole tower and a sleeve surrounding the pole. The pole and the sleeve are anchored to a foundation. The sleeve supports the load. A number of sleeves may be used with a first sleeve anchored to the foundation, a second sleeve supporting the load, and one or more joinder sleeves positioned between the first sleeve and the second sleeve. The pole also may support a second load. The total height of the number of sleeves may extend beyond the height of the existing single pole tower. A number of load transfer pins may be positioned along the sleeve. The pins extend from the sleeve to the pole so as to stabilize the load.
A method of the present invention provides for placing an additional load on a single pole tower. The single pole tower includes a pole anchored to a foundation. The method includes the steps of positioning one or more sleeves around the pole, anchoring the sleeves to the foundation, and supporting the additional load on the sleeves. A first one of the number of sleeves may be anchored to the foundation, a second one of the sleeves may be supporting the additional load, and one or more joinder sleeves may attach the first and the second sleeves. The method may further include the step of attaching a number of load transfer pins to the sleeves so as to stabilize the additional load.
Thus, it is an object of the present invention to provide an improved method and apparatus for increasing the capacity and stability of a single-pole tower.
It is another object of the present invention to provide an improved method and apparatus for increasing the capacity and stability of a single-pole tower wherein the apparatus will support the weight of additional equipment and the additional environmental forces exerted on the pole.
It is still another object of the present invention to provide an improved method and apparatus for increasing the capacity and stability of a single-pole tower wherein the apparatus will support the weight of additional equipment and the additional environmental forces exerted on the pole while also providing sufficient stability to resist the forces known as bending moments caused by the new equipment and the environmental forces.